Stair tread marking gauge



FIG. 1 is a front, top, left side isometric perspective view of a stair tread marking gauge in accordance with my design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a partial enlarged cross-sectional view of the stair tread marking gauge shown looking in the direction indicated by line 8-8 of FIG. 6 .

The dash-dash broken lines represent environmental subject matter that form no part of the claimed design.

The dot-dot-dash broken lines represent breakaway lines and form no part of the claimed design;

The claimed design is shown with symbolic breaks in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design. 

CLAIM The ornamental design for a stair tread marking gauge, as shown and described. 